//背景图片
bg-image($url)
	background-image: url($url + "@2x.png")
	@media (-webkit-min-device-pixel-ratio: 3),(min-device-pixel-ratio: 3)
		background-image: url($url + "@3x.png")

//不换行
no-wrap()
	text-overflow: ellipsis
	overflow: hidden
	white-space: nowrap

//1px 边框
border-1px($color)
	position : relative
	&:after
		display : block
		position : absolute
		left : 0
		top : 0
		width : 100%
		border-top : 1px solid $color
		content : ' '

@media (-webkit-min-device-pixel-ratio: 1.5),(min-device-pixel-ratio: 1.5)
	.border-1px
		&::after
			-webkit-transform: scaleY(0.7)
			transform: scaleY(0.7)

@media (-webkit-min-device-pixel-ratio: 2),(min-device-pixel-ratio: 2)
	.border-1px
		&::after
			-webkit-transform: scaleY(0.5)
			transform: scaleY(0.5)

//没有边框
border-none()
	&:after
		display : none
